Hello, On Thu, Sep 24, 2020 at 03:20:33AM +0000, Qiang Zhao wrote: > On 21/09/2020 13:48:19+0800, Qiang Zhao wrote: > > > -----Original Message----- > > From: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> > > Sent: 2020年9月23日 17:45 > > To: Qiang Zhao <qiang.zhao@xxxxxxx> > > Cc: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>; Guenter Roeck > > <linux@xxxxxxxxxxxx>; linux-watchdog@xxxxxxxxxxxxxxx; > > a.zummo@xxxxxxxxxxxx; robh+dt@xxxxxxxxxx; linux-rtc@xxxxxxxxxxxxxxx; > > devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Uwe Kleine-König > > <u.kleine-koenig@xxxxxxxxxxxxxx> > > Subject: Re: [Patch v2 1/3] dt-bindings: rtc: pcf2127: Add bindings for > > nxp,pcf2127 > > > > Hi, > > > > You forgot to copy the watchdog maintainers, I think such a property should be > > discussed with them. > > > > Note that I'm still convinced this is not a complete solution, see: > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kern > > el.org%2Flinux-rtc%2F20200716181816.GF3428%40piout.net%2F&data= > > 02%7C01%7Cqiang.zhao%40nxp.com%7Cb71f79a044b0493d6d4f08d85fa551c > > b%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C1%7C637364510931174 > > 355&sdata=%2BOxrzB8RIuxM9Let5slhfCVmMm6PMNoERDeHC9%2Fdxng > > %3D&reserved=0 haha > Yes, you are right, There is not a fundamental solution. > However it somewhat avoid this situation at least. > > And if without this issue, > is it correct to register a rtc device as watchdog no matter it is used as watchdog on the board? > Every time Linux are booted up, watchdog device should be configured to the right one manually. > So the patch are useful, even though it is not for the issue. > > What should we do to really resolve this issue? I still think we need a kernel solution here. I would expect that most assembled pcf2127 chips are unable to act as a watchdog (i.e. don't have the RST output connected to something that resets the machine). So my favoured solution would be a positive property like: has-watchdog; or something similar. In my eyes this is definitely something we want to specify in the device tree because it is a relevant hardware property. I consider it a bug to give a watchdog device to userspace that isn't functional. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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